Fair Value Hierarchy for Financial Assets (Cash Equivalents and Investments) Measured at Fair Value on Recurring Basis (Detail) - USD ($) $ in Thousands	Aug. 01, 2015	Jan. 31, 2015	Aug. 02, 2014	Feb. 01, 2014
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	$ 327,290	$ 410,697	$ 262,628	$ 418,933
Total	327,290	410,697	262,628
Cash
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	248,824	370,692	186,840
Money-market
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	78,466	$ 40,005	53,606
Treasury bills
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents			22,182
Fair Value, Measurements, Recurring | Quoted Market Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	327,290		262,628
Total	327,290		262,628
Fair Value, Measurements, Recurring | Quoted Market Prices in Active Markets for Identical Assets (Level 1) | Cash
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	248,824		186,840
Fair Value, Measurements, Recurring | Quoted Market Prices in Active Markets for Identical Assets (Level 1) | Money-market
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	$ 78,466		53,606
Fair Value, Measurements, Recurring | Quoted Market Prices in Active Markets for Identical Assets (Level 1) | Treasury bills
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents			$ 22,182